This project which seeks to determine whether individuals who access the "911" emergency medical system (EMS) with acute myocardial infarction (MI) or unstable angina will receive more timely hospital treatment and better outcomes if hospital clinicians are provided with 1) earlier, and 2) more complete ECG information. Earlier EKG information will be achieved in 2 ways: (1) by synthesizing a 12-lead ECG from a rapidly applied 5 electrode configuration, rather than using the cumbersome 10- electrode configuration required for a standard 12 lead ECG, and (2) by transmitting ECGs by cell phone tele-electrocardiography) from the field to the emergency department (ED) rather than waiting to obtain an ECG after hospital arrival. More complete ECG information will be achieved in 3 ways 1) by monitoring continuously rather than recording a one-time ECG, 2) by monitoring all 12 EKG leads, rather than a single lead, and (3) by monitoring with special ischemia detection software, rather than arrhythmia software alone. The software will continuously analyze ST segments in all 12 ECG leads for changes of acute ischemia and will automatically print out ECGs in the ED when ST events occur. This tele-electrocardiography intervention will be implemented as a county wide program in Northern California through Santa Cruz County's EMS. A total of 2,468 subjects will be recruited for this prospective, randomized controlled clinical trial. Subjects will be randomized to one of two groups: 1) the experimental group will have the pre-hospital tele-electrocardiography intervention and 2) the control group will have routine EMS cardiac care. Hypotheses to be tested are that patients randomized to the ST SMART intervention experimental group will, in comparison to patients in the routine EMS control group have: (1) no longer paramedic scene times, despite the acquisition of more ECG information, (2) reduced time to treatment for acute coronary syndromes, and (3) fewer adverse outcomes in the hospital and at one year following hospital discharge.